Combining Near-Infrared Spectroscopy and Chemometrics for Rapid Recognition of an Hg-Contaminated Plant

Abstract

The feasibility of rapid recognition of an Hg-contaminated plant as a soil pollution indicator was investigated using near-infrared spectroscopy (NIRS) and chemometrics. The stem and leave of a native plant, Miscanthus floridulus (Labill.) Warb. (MFLW), were collected from Hg-contaminated areas ( 1 = 125) as well as from regular areas ( 2 = 116). The samples were dried and crushed and the powders were sieved through an 80-mesh sieve. Reference analysis of Hg levels was performed using inductively coupled plasma-atomic emission spectrometry (ICP-AES). The actual Hg contents of contaminated and normal samples were 16.2-30.5 and 0.0-0.1 mg/Kg, respectively. The NIRS measurements of impacted sample powders were collected in the mode of reflectance. The DUPLEX algorithm was utilized to split the NIRS data into representative training and test sets. Different spectral preprocessing methods were performed to remove the unwanted and noncomposition-correlated spectral variations. Classification models were developed using partial least squares discrimination analysis (PLSDA) based on the raw, smoothed, second-order derivative (D2), and standard normal variate (SNV) data, respectively. The prediction accuracy obtained by PLSDA with each data preprocessing option was 100%, indicating pattern recognition of Hg-contaminated MFLW samples using NIRS data was in perfect consistence with the ICP-AES results. NIRS combined with chemometrics will provide a tool to screen the Hg-contaminated MFLW, which can be potentially used as an indicator of soil pollution.

Partial Least Squares-Discriminant Analysis Classification for Patchouli Oil Adulteration Detection by Fourier Transform Infrared Spectroscopy in Combination with Chemometrics

“…The next factor (3–5) only experienced a small and insignificant increase. In other words, the success of this model is sufficiently contributed by factor-1 and factor-2. ,− …”

“…Normalization is applied to adjust the magnitude of the peaks to a common scale and helps to eliminate the effects of instrument drift and variability. These pre-processing methods are commonly used in the analysis of spectroscopic data and have been proven to enhance the quality and accuracy of the results. − …”

“…These pre-processing methods are commonly used in the analysis of spectroscopic data and have been proven to enhance the quality and accuracy of the results. 46 − 48 …”

Rapid Detection of Pesticide Residues in Chinese Herbal Medicines by Fourier Transform Infrared Spectroscopy Coupled with Partial Least Squares Regression

“…For ease of peak attributions, chemical bonds are denoted as atomatom, where an atom can be carbon (C), hydrogen (H), oxygen (O), and nitrogen (N). For the NIR spectra of multipesticide residues in Radix Angelicae Dahuricae samples as shown in Figure 1(a1), it can be seen that the characteristic absorption peaks can be interpreted as follows [33,34]: the peak 4251 cm −1 is the C-H stretch/C-H deformation in the phenyl or CH 2 bend second overtone and around 4340 cm −1 can be attributed to the combination absorbance of C-H antisymmetric stretching and C-H bending. Around 4686 cm −1 peak brand is due to the combination stretching vibration of C=C, =C-H bands and combination of the base bands of N-H stretching and bending; peak 5180 cm −1 can be explained as second overtone of C=O stretching bands, stretching first overtone of C-H bands in aromatic rings and combination of the basebands of O-H stretching and bending.…”

Electrochemical Characterization and Detection of Lead in Water Using SPCE Modified with BiONPs/PANI

“…However, the detection of heavy metals is a complicated procedure, often involving widespread processes of preparation of sample leading to the measurement, when analytical techniques are employed [15]. Such standard techniques for the detection of heavy metal ions such as inductively coupled plasma optical emission spectrometry (ICP-OES) [16][17][18], UV-Vis spectrometry, [19][20][21] atomic absorption/emission spectroscopy [22][23][24] and laser-induced breakdown spectroscopy (LIBS) [25,26], would not be suitable for in situ, fast, easy and low-cost operation.…”